This disclosure relates to articles comprising reversibly attached screws comprising a biodegradable composition, methods of manufacture thereof and uses thereof.
Orthopedic implants are medical devices which are surgically implemented in order to repair/support an injury to a bone or to replace a damaged bone in a living being. Implementation of the implant, also known as “internal fixation”, anchors the bones in which they are implanted, thereby facilitating healing of the injury.
Non-biodegradable implants suffer from various drawbacks. Non-biodegradable implants may present biocompatibility concerns over time if the implant is not removed from the living being. Non-biodegradable implants may also involve a second surgical procedure in order to remove the implant after healing is complete. Non-biodegradable implants (e.g., titanium implants) may also be significantly stronger than the bone in the living being in which they are employed. This difference between the strength of the bone compared to the relative strength of the implant leads to stress shielding. Stress shielding occurs when the implant bears bodily stress, rather than sharing the bodily stress with the bone, due to the much higher relative strength of the implant. Stress shielding in turn leads to bone atrophy.
Biodegradable orthopedic implants may avoid biocompatibility issues; however, biodegradable implants which are based upon polymers have significantly lower strength than non-biodegradable implants. Such biodegradable implants also have a high degradation rate and/or degradation is incomplete, resulting in an undesirable residual pool. Biodegradable orthopedic implants are thus limited to low-load implant applications. Biodegradable implants may also employ specialized equipment, surface pre-treatments and/or simplified substrate geometries.
It is therefore desirable to develop an article which avoids the above-described problems, reduces stress shielding, improves stress sharing, is suitable in high-load applications, does not form a residual pool after degradation, is produced without specialized equipment, surface pre-treatments and/or restricted substrate geometries and/or positively influences bone growth and/or the healing process, when the article is used in the body of a living being.